add missing method doc

docs/api/en/core/BufferAttribute.html

@@ -120,6 +120,9 @@
 		<h3>[method:BufferAttribute clone]() </h3>
 		<p>Return a copy of this bufferAttribute.</p>
 
+		<h3>[method:BufferAttribute copy]( [param:BufferAttribute bufferAttribute] )</h3>
+		<p>Copies another BufferAttribute to this BufferAttribute.</p>
+
 		<h3>[method:BufferAttribute copyArray]( array ) </h3>
 		<p>Copy the array given here (which can be a normal array or TypedArray) into
 			[page:BufferAttribute.array array].<br /><br />